Gelled glycerol fatty acid partial ester pharmaceutical carrier



U i d m. P fin GELLED G LYCE'ROL FATTY ACID PARTIAL ESTER PHARMACEUTICAL CARRIER No Drawing. Application April 19, 1957 Serial No. 653,728

7 Claims. (Cl. 167-81) This invention relates to glycerol fatty acid partial ester compositions and more particularly, to high purity monoglyceride compositions.

High purity monoglyceride compositions can be readily prepared by the methods disclosed by Kuhrt in U.S. Patents 2,634,234, 2,634,278 and 2,634,279. In accordance with Kuhrts'methods, a fatty material such as a triglyceride or a fatty acid is interesterified with glycerine in the presence of an interesterification catalyst. The resulting interesterification reaction mixture is thereafter subjected to thin film high vacuum distillation to separate a high purity monoglyceride composition. A

It'is an object of this invention to provide high purity monoglyceride compositions in a new and useful form.

It is another object of this invention to provide high purity monoglyceride compositions in an improved form that is particularly suitable as a carrier material for medicaments.

It. is a further object of this invention to provide low melting, high purity, distilled monoglyceride compositions in a new and useful form.

These and other objects are attained by means of this invention as described hereafter with particular reference to certain preferred embodiments.

In accordance with the invention, new and useful gels can be formed with water and certain especially prepared glycerol fatty acid partial ester compositions.

The glycerol'partial ester compositions employed to prepare the present gels contain atIleast 75%, desirably at least 85%, and preferably at least 90% by weight of monoglycerides having fatty acid radicals with at least ,16, carbon atoms and more generally from 16 to 22' carbon atoms. Also, the glycerol partial ester compositions used inthe present invention contain less than 10% and preferably less than 5% by weight of glycerides having saturated fatty acid radicals with more than 11 carbon atoms. Partial ester compositions containing glycerides :havingsuch 18 carbon atom unsaturated fatty acid radicals asoleic, linoleic andlinolenic acid radicals, and admixtures ,in all proportions-thereof, are preferably employed. Particularly suitable arehigh purity, normally liquid partial ester. compositions comprised of a major proportion of such polyunsaturated monoglycerides as monolinolein. aiidmonolinolenin or admixtures thereof. ,Commercial oleicacidmixtures which contaimat least 90% [by weight ofoleic acid can be utilized to prepare vthe partial ester compositionsused in the present gels.

' Also, the partial ester compositions can be prepared from solvent wintered fatty acid mixtures prepared by saponifying and acidulating, such glyceride materials as cottonseed oil, corn oil, poppyseed oil, sunflower oil, safflower oil, linseed oil, peanut oil, soybean oil and the like, the solvent wintering removing substantial amounts of such saturated fatty acids as stearic acid, palmitic acid, myristi c -acid and lauric acid from the mixtures. For example, a fatty acid mixture consisting essentially of linoleic "acid and oleic acid can be prepared from saponified and acidulated cottonseed. oil fatty acids by dissolving a catalyst.

cottonseed oil fatty acid mixture in an equal weight of acetone, chilling the mixture to 15 C. and holding the mixtureat this temperature for 24 hours, filtering out the resulting crystallized higher saturated fatty acids, and thereafter distilling the acetone from the filtrate to recover a fatty acid mixture suitable for preparing the high purity monoglyceride compositions used in making the gels described herein. Similarly, a fatty acid mixture consisting essentially of oleic acid, linoleic acid and linolenic acid can be prepared by wintering a linseed oil fatty acid mixture.

The present glycerol fatty acid partial ester compositions can be prepared by reacting glycerol and triglycerides or fatty acids containing the suitable fatty acid moieties described above in the presence of a basic interesterification catalyst, and thereafter separating by thin film high vacuum distillation a composition containing at least by weight of monoglyceride, the balance consisting essentially of diglycerides and triglycerides.

Any of the well known alkali metal and alkaline earth metal interesterification catalyst materials can be employed as the catalyst to prepare the present glycerol fatty acid partial ester compositions. Particularly suited are the alkali and alkaline earth metal oxides, hydroxides, carbonates, alcoholates, hydrides and glyceroxides. Particularly effective are the bivalent metal compounds such as calicum oxide, barium oxide, strontium oxide, strontium hydroxide, calcium hydroxide, barium hydroxide, etc. Likewise, the catalyst can be added to the reaction mixture in the form of such soaps as sodium stearate,

-chiometric proportions based on the weight of the fatty acidsor triglycerides in the reaction mixture. Thereaction is effectedat elevated temperatures for optimum results, with temperatures of at least 180 C. and particularly temperatures from about 200 C. to about 280 C. being eminently suitable. The reaction time is usually varied from about 15 minutes to about 6 hours depending upon the ratio of the reactants, concentration of catalyst; reaction temperature and similar variables which afiectthe speed of the reaction. a

- The resulting reaction mixture is preferably cooled and a largeproportion of the'unreacted glycerol phased oif. Thereafter, the remaining unreacted glycerol is distilled or'stripped offthe reaction-mixture by thin film vacuum -distillation,'typical distillation conditions being pressures of 10 micronsat f" C. to 300 microns at C. A glycerol fatty acid partial ester composition is then distilled from the reaction mixture, typical distillation conditions being pressures of from 1micron'at 150. C; to 10 microns at 200 C. I The pressures referred to above are in microns of mercury. Such distillation conditions are merely illustrative and considerable variations can be made in accordance with usual distillation practice, High vacuum thin film'centrifugal distillation is desirablyemployed for separating the partial ester. composition. -.The interesterification reaction mixture is readily spread in a thin film, usually less than 5 mm. and more generally less than 1 mm. in thickness, on the heated distilling surface of the still, and the'partial ester. composition rapidly distilled therefrom. The distillati'ons, are made without prior killing or inactivationjof.theinteresterification Patented July 21, 1 959 of strontium hydroxide.

The present gels are prepared by incorporating water into the above described glycerol fatty acid partial ester compositions. As the amount of water incorporated into 'the present partial ester compositions is increased, the gel becomes increasingly firmer until no more water can be incorporated. Waterin amounts of at least 10% 'of but less than 90% .of the weight of'the partial ester composition, and preferably from 15% to 50% by weight ofthe weight of the partial ester composition is incorporated into the partial ester composition .to form the present gels. The present 'gels can be readily formed by com- 'bining the partial ester composition with water and heating the resulting mixture until a gelatinous composition is formed. A firm, substantially clear gel is formed on cooling which resembles in appearance petroleum jelly. Gels containing up to about 40% by weight of water basedon the partial ester compositionican be prepared by this method. Also, the present gels can be prepared by thoroughly mixing or kneading the partial estercomposition and Water at room temperature. Up to about 90% by weight of water based on the partial ester composition can be incorporated into the partial ester composition by such a mixing or kneading action. Uncom bined or excess water can be easily separated by decanting or pouring it from the gel. X-ray difiraction patterns of the present gels indicatethat they are in an amorphous form. The common mono-diglyceride mixtures of commerce which contain about 40% to 50% monoglyceride, about 40% to 50% diglyceride and about to 20% triglyceride do not form gels with water as do the present high .purity monoglyceride compositions.

The gels of the present invention can be employed in a diversity of products such as in cosmetics and related products. Likewise, the present gels can be used as carrier materials for medicaments. Medicamlents can be incorporated into the gel in amounts up to about 15%, although much smaller amounts are usually employed. Such medicaments as vitamins, amines, enzymes, hormones and the like can be incorporated into the gel. As the present gels are combinations of water and fatty materials, these gels can be utilized as carrier materials for water soluble and fat soluble medicaments and admixtures thereof. Thus, for example, a multi-vitamin gel containing both water soluble and fat soluble vitamins can be prepared. Typical of the vitamins that can be incorporated into the present gels are such water soluble vitamins as thiamin, riboflavin, pyridoxin, nicotinic acid,

pantothenic acid, inositol, p amino benzoic acid and vitamin C; and such fat soluble vitamin materials as vitamin A and fatty acid esters thereof, beta-carotene, vitamin D, vitamin E and fatty acid-esters thereof, and vitamin K. To prepare a gel containing water soluble and fat soluble medicaments, the water soluble medicament is dissolved in water, the fat soluble medicament is dissolved in a glycerol fatty acid partial ester composition, and thereafter the medicament-containing aqueous solution is incorporated into the medicament-containing fatty acid partial ester composition to form a gel as described hereinabove.

The invention is illustrated by the following examples of preferred embodiments thereof.

Example 1 comprised of about 57% linoleic acid, about 40% oleic acid, about 2% linolenic acid and about 1% palmitic acid, was added 7.5 kilograms of glycerol and 14 grams The resulting mixture was heated to 250 C. and maintained at that temperature for 60 minutes during which time the resulting water of esterification was allowed to evaporate from the reaction mixture. The reaction mixture was then cooled and a substantial portion of the unreacted glycerol decanted therefrom. Substantially all of the remaining glycerol was next distilled from the remaining mixture at a pressure of about 10 microns of mercury and at a temperature of 130 C. on a centrifugal, thin film, molecular still having a 14-inch rotor. Thereafter the temperature of the distillation was raised to 180 C., the pressure being maintained at about 10 microns of mercury, and a glycerol partial ester composition distilled over. The resulting distilled product contained about 95% by weight of monoglyceride, was liquid at room temperature, remained a clear liquid to about 23 C., congealed at about 14.5 C. and had an iodine value of 110.

(a) A 10 gram portion of the distilled glycerol partial ester composition was thoroughly stirred with 2.8 grams of water at room temperature. A transparent, firm, gel resulted.

(b) 8 parts by weight of the distilled glycerol partial ester composition, 2 parts by weight of cottonseed oil and 2 parts by Weight of water were thoroughly stirred at room temperature.- A firm, substantially clear gel resulted.

Example 2 A distilled glycerol partial ester composition was prepared by the method described in Example 1 except that USP oleic acid was used in lieu of the fatty acid mixture used in the reaction mixture in Example 1. The resulting distilled glycerol partial ester composition contained about 95 by Weight of monoglyceride, was a soft white solid at room temperature, melted to clarity at 35 C. and had an iodine value of about 70.

(a) Portions of the distilled glycerol partial ester composition prepared froml oleic acid were heated at about C. with varying amounts of water and the resulting mixtures cooled to about 20 C. to form compositions having varying physical properties as indicated in the following table. The proportions of partial ester composition and water set out in the table are indicated in percent by weight.

Partial ester Water Physical State at 20 0. Composition Percent Percent 10 Soft, opaque solid.

5 Translucent, pourable gel. 90 10 Transparent, firm gel. 67 33 Do.

comprised of about 10 parts by weight of partial ester composition and 9 parts by weight of water.

(a) A 5 .gram sample of a vitamin A acetateconcentrate prepared by chemical synthesis and having a potency of about 2,600,000 USP units per gram was dis solved in 50 gramsof the distilled glycerol partial ester composition prepared from oleic acid. Thereafter, 15 grams of a 1% aqueous nicotinic acid solution were added. The resulting mixture. was liquefied by heating to about 60 C. On cooling to room temperature, the hquefied mixture formed a multivitamin-containing gel having the general appearance of petroleum jelly.

(d) An 87 gram sample of the distilled glycerol partial ester composition prepared from oleic acid was intimately mixed with 180 grams of water at a temperature of about 50 C. This mixture was then cooled to room temperature, excess Water poured off, and a clear, firm gel Weighmg 129.3 grams resulted. The gel remained stable in a clear, firm statefor more than 18 months at room temperature in a closed container.

While the invention has been described in considerable detail with reference to certain preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A firm, substantially clear gel comprising a glycerol fatty acid partial ester composition containing at least 75% by 'weight of monoglycerides having fatty acid radicals with at least 16 carbon atoms and having incorporated therein water in an amount of from to 90% by weight based on said glycerol fatty acid partial ester composition and a medicament in amounts up to about by weight based on said glycerol fatty acid partial ester composition, said glycerol fatty acid partial ester composition containing less than 10% by weight of glycerides having saturated fatty acid radicals with more than 11 carbon atoms.

2. A firm, substantially clear gel comprising a distilled glycerol fatty acid partial ester composition containing at least 90% by weight of monoglycerides having fatty acid radicals with at least 16 carbon atoms and having incorporated therein water in an amount of from 10% to 90% by Weight based on said glycerol fatty acid partial ester composition and a medicament in amounts up to about 15% by weight based on said glycerol fatty acid partial ester composition, said glycerol fatty acid partial ester composition containing less than 5% by weight of glycerides having saturated fatty acid radicals with more than 11 carbon atoms.

3. A firm, substantially clear gel comprising a distilled glycerol fatty acid partial ester composition containing at least 90% by weight of monoglycerides having fatty acid radicals with at least 16 carbon atoms and having incorporated therein Water in an amount of from 10% to 90% by weight based on said glycerol fatty acid partial ester composition and a medicament selected from the class consisting of water soluble vitamins and fat soluble vitamins in amounts up to about 15 by weight based on said glycerol fatty acid partial ester composition, said glycerol fatty acid partial ester composition con taining less than 5% by weight of glycerides having saturated fatty acid radicals with more than 11 carbon atoms.

4.A firm, substantially clear gel comprising a distilled glycerol fatty acid partial ester composition containing at least-90% by Weight of monoglycerides having unsaturated fatty acid radicals with 18 carbon atoms and having incorporated therein water in an amount of from 10% to by weight based on said glycerol fatty acid partial ester composition and a water soluble vitamin in amounts up to 15% by weight based on said glycerol fatty acid partial ester composition, said glycerol fatty acid partial ester composition containing less than 5% by weight of glycerides having saturated fatty acid radicals with more than 11 carbon atoms.

5. A firm, substantially clear gel comprising a distilled glycerol fatty acid partial ester composition containing at least 90% by Weight of -monoglycerides having unsaturated fatty acid radicals with 18 carbon atoms and having incorporated therein water in anamount of from 10% to 90% by weight based on said glycerol fatty acid partial ester composition and a fat soluble vitamin in amounts up to 15% by Weight based on said glycerol fatty acid partial ester composition, said glycerol fatty acid partial ester composition containing less than 5% by Weight of glycerides having saturated fatty acid radicals with more than 11 carbon atoms.

6. A composition as defined by claim 5 wherein the fat soluble vitamin is a vitamin A fatty acid ester.

7. A firm, substantially clear gel comprising a distilled glycerol fatty acid partial ester composition containing at least 90% by weight of monoglyceride having oleic acid radicals and having incorporated therein water in an amount of from 10% to 90% by weight based on said glycerol fatty acid partial ester composition and a medicament in amounts up to about 15 by weight based on said glycerol fatty acid partial ester composition, said glycerol fatty acid partial ester composition containing less than 5% by weight of glycerides having saturated fatty acid radicals with more than 11 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 2,391,255 Marshall Dec. 18, 1945 2,512,435 Mitchell June 20, 1950 2,573,650 Peterson Oct. 30, 1951 2,625,501 Salb Jan. 13, 1953 2,634,278 Kuhrt Apr. 7, 1953 2,634,279 Kuhrt Apr. 7, 1953 2,738,303 Blythe Mar. 13, 1956 2,768,112 Buckwalter Oct. 23, 1956 2,797,185 Campbell June 25, 1957 2,798,023 Berger July 2, 1957 FOREIGN PATENTS 532,369 Canada Oct. 30, 1956 

1. A FIRM, SUBSTANTIALLY CLEAR GEL COMPRISING A GLYCEROL FATTY ACID PARTIAL ESTER COMPOSITION CONTAINING AT LEAST 75% BY WEIGHT OF MONOGLYCERIDES HAVING FATTY ACID RADICALS WITH AT LEAST 16 CARBON ATOMS AND HAVING INCORPORATED THEREIN WATER IN AN AMOUNT OF FROM 10% TO 90% BY WEIGHT BASED ON SAID GLYCEROL FATTY ACID PARTIAL ESTER COMPOSITION AND A MEDICAMENT IN AMOUNTS UP TO ABOUT 15% BY WEIGHT BASED ON SAID GLYCEROL FATTY ACID PARTIAL ESTER COMPOSITION, SAID GLYCEROL FATTY ACID PARTIAL ESTER COMPOSITION CONTAINING LESS THAN 10% BY WEIGHT OF GLYCERIDES HAVING SATURATED FATTY ACID RADICALS WITH MORE THAN 11 CARBON ATOMS. 